Proper maintenance of industrial machinery generally includes frequent removal of undesired accumulations of particles on different elements of the machinery. Particles accumulation on the machinery parts can be minimalized by cleaning the environment surrounding the machinery. Various air cleaning devices have been used for that purpose.
Although a clean working environment reduces particle accumulation on the machinery parts, it cannot prevent such accumulation completely. Thus, more direct methods for cleaning the machinery parts are often required.
It is known that efficient cleaning of various machinery parts may be achieved by generating shock waves in the vicinity of the parts thereby "shaking off" dust particles and other accumulations from the parts. Alternatively, the shock waves may be induced onto a machinery part, causing the part to vibrate and "shake off" the accumulations. Shock wave cleaning is particularly useful for elements which are not readily removed for cleaning and/or elements which are particularly susceptible to the use of other cleaning methods and/or cleaning materials.
Gas dynamic generators which induce shock wave vibrations in their vicinity are known in the art. When a gas dynamic generator is placed near a machinery element to be cleaned, the shock waves induced in the vicinity of the element can be utilized to clean the element, as described above. Gas dynamic generators are useful aids in the production of construction materials and apparatus, metallurgy, mining, the chemical industry, oil processing and the food industry.
Gas dynamic generators have been used in the past, for example, for cleaning dust accumulation and other deposits in a centrifugal compressor. The centrifugal compressor includes a pumping wheel with pumping blades mounted in a pumping chamber. Nozzles, which are connected to a source of pressured gas via a gas channel, are mounted in the pumping chamber at a preselected distance from the pumping blades. The source generates high pressure gas pulses which impinge on the pumping blades thereby removing undesired accumulations from the blades. For optimal results, the distance between the nozzles and the pumping blades is selected to be between 1 and 1.5 times the diameter of the gas channel.
Gas dynamic generators have also been used for cleaning contaminated electrodes, particularly for purifying electrodes of electrofilters. An ignited air-fuel mixture is transported through an elongated detonation chamber, in which the burning mixture develops a high velocity, and is released onto a shock receiving plate which is associated with a shock transporting block. The block carries shock waves produced in the plate to the electrodes, thereby causing high acceleration vibrations in the electrodes to "shake off" the deposits.
Although existing gas dynamic pulse generators are useful for some applications, such as for cleaning compressor blades and removing deposits from electrodes, these systems generally suffer from high energy consumption and low operating efficiency. The output pressures obtained by devices as described above generally does not exceed 10-12 bars and, even then, most of the gas dynamic energy is not utilized since only a fraction of the pulsed gas dynamic energy is converted into shock waves in the part to be cleaned. Additionally, since the burning rate of the air-fuel mixture is relatively low (typically 400-500 meters per second) compared to the expansion rate of the mixture, only part of the mixture (typically non more than 30%) is utilized to produce the gas dynamic pulses. This difference between the burning rate and the expansion rate may also result in undesirable release of a flammable air-fuel mixture, thereby reducing the efficiency of the system and endangering the persons operating the system.